Typewriting machine



March 18 192410 1,487,513

M". GARBELL TYPEWRITING MACHINE Filed May 51. 1921 3 Sheets-Sheet 1 Marsh 18 192% 7,513

- M. GARBELL Y TYPEWRITING MACHINE Filed May 31, 1921 3 Sheets-Shad 2 fmwfor W Ma-I'Ch 1924a M. GARBELL TYPEWRITING MACHINE Filed May 51, 1921 3 Sheets-Sheeii' 5 Patented Mar. 18, 1%24.

time eras MAXGARBELL, or cnrcnoo, ILLINOIS, Assrenos, BY iunsnn ASSIGNIVIEN'TS, no 0. 1). assumes & colvrrsnv, or cnrcaoo, ILLINQIS, a cosrosnrron or rumors.

TYPEVR-ITING IHACHINE.

Application filed May 31, 1921.

H1 1 1 ad whom it may concern:

Be 1t known that 1, MAX G-ARBELL, a citi Zen of the United States, residing at hicago, in the county of Cool; and State of 5 Illinois, have invented a certain new and useful Improvement in Typewriting Machines, of which the following is a full, *clear, concise, and exactdescription, reference being had to the accompanying drawings, forming a part of thisspecilication.

This invention relates to improvements in typewriting machines.

One objector my invention is to provide a typcwriting machine having an improved positively and uni'tormly-acting back-spac ing arrangement opera 710 in any case shift position of the platen.

'More specifically, the object of my invention is to provide a baclespacm arrangement of a nple, economical and etlicient operation, which is particularly adapted for typewriters having a removable platen and platen frame, and wherein the parts of the ham-spacer mechanism are unailected by the 'removal or replacement of the platen and trains carr the same.

More sp lically, an objectof my in vention is to provide a back-spacer arrangement for typewriters, which back spacer arrangement may be manufactured and assembled as a unit and then applied as a trait to the platen carriage. Qther objects of the invention will more clearly appear from the description and claims hereinafter appearing.

In the drawings forming a part of this specification, Figure 1 is a part elevational view, part vertical sectional view looking at the back of a typewriter, some of the parts being also broken away to more clearly illustrate the details of construction. In this figure, the back-spacer mechanism is shown in its inoperative or normal condition. Fig. 2 is a view similar to Fig. 1 but Serial No. 474,029.

trating the position assumed by the parts at the end of the actuating stroke of the backs iacer key. And Fig. 5 is avertical sectional view taken from the front to the back of the typewriter showing more particularly the back-spacer key and operative connections therefrom to the back-spacer mechanism proper. The full lines illustrate the normal or inoperative position of the parts and the dotted lines the position assumed by the parts at the end of. the depression of the hack-spacer key.

In the drawings 1 have only deemed it necessary to illustrate such parts of the typewriter as are directly concerned with the back-spacer mechanism, and sufficient of the arrangement of the removable platen carriage to illustrate my improvements in 1 such typeot a typewriter. For a more comple'te disclosure of the other details of the typewriter and removable platen carriage, reference may be had to my prior Patent No. 1,305,893, granted. June 3, 1919, and my pending applications 860,958, filed February 24-. 1920, and 4641.133. filed April 25,1921.

In the drawings forming part of this specification, the main frame of the machine is indicated at 10, the same having a back wall '10 and mounted upon suitable cushions Lil-11. A bridge 12 extends crosswise of the typewriter, said bridge be ing shown in section in Fig. 5. A baclspacer lrey 13 is also shown, the same being of the usual or desired form and pivoted on a transversely extending pivot rod 14:. A retracting spring 13 is connected at one end to said lever 13 and at its other end to the bridge 12. Pivotally connected to the inner end of the back-spacer key lever is a lever 15 pivotally mounted on the pivot screw 16, as indicated in Fig. 5. The pivotal connection between the spacer lever 13 and lever 15 may be of any approved form, the same shown comprising an enlarged headed pin 17 on the lever 15, which is adapted to be first inserted through an enlarged opening 18 in the spacer lever 13 and then slipped lengthwise into a communicating slot 19.

At its opposite end, the lever 15 1s plvotally connected by an enlarged headed pm 20 with twisted sheet metal link 21, which in turn is pivotally connected, as indicated at 22 (see Figs. 1 and 2), with a right angled lever 25. One arm of said lever 25 is pivotally attached'to the hack all ill of the main frame, as indica ed at 126, to thereby adapt the lever 25 to oscillate in a vertical plane parallel with the back wall 10 The lever 25 has an upwardly extending arm, which is offset inwardly of the machine, as indicated at 26.

The removable platen carriage (and by the terms platen carriage I mean to include the platen proper, the frame directly carrying the platen proper and the subframe along which the platen frame is longitudinally movable in a well-known manner) isshown as having a platen roller proper 27, a longitudinally extending rail 28, a longitudinally extending spacer rack 29, rigid with espect to the platen frame but adapted for limited. vertical adjustment with respect thereto by means of set scr we 30 and elongated slots 31, and a paper-feed guide 62. The carriage is made removable with respect to the main frame of the typewriter by suitable means-such as shown in my said application 360,958 and application 464,133. rieiiy stated the sub-frame of the carriage is provided with a pair of laterally-spaced rigid guides suitably apertured to slide vertically up and down a pair of guide posts 83 mounted on the main frame of the machine.

As is customary in typewriters, I provide a spring motor, as indicated conventionally at 34: in Figs. 1 and 2, which is operatively connected with a gear wheel 35, the latter having geared engagement with the spacer rack bar 29, the function of the spring motor being to advance the platen carriage automatically step by step as the printing takes place, the carriage ordinarily being returned the full distance by direct manual shifting, as will be understood. Said spring motor is carried on a relatively heavy pivot screw 36, which, in turn, is supported on a stamped and formed )late 37 rigidly attached to the sub-frame of the carriage.

In the drawings I have also illustrated a desirable form of escapement mechanism, said escapement mechanism comprising a pinion 88 in mesh with the rack bar 29 and a ratchet wheel 39 united to the pinion 38, both being loosely rotatably mounted on the shaft e 0. Cooperable with the ratchet wheel. 39 is a pawl 11, which is pivotally and slidably mounted by means of the pivot pin 12 and slot l8 on an oscillating plate 141-. Said plate 1 is in turn pivotally mounted to swing about a horizontal axis on the bracket plate 37 by means of adjustable pivot screws 45- 1 5. A coiled spring 46 is attached to a depending arm 47 of the pawl 41 and to a shoulder 18 carried by the plate a l. Said plate 14 also carries a tooth rigid or inte ral therewith (broken away, however, to avoid confusion in the drawings), which tooth will alternate with the pawl 4:1 in engagement with the ratchet wheel 39 to effect the step by step escapement or advancement of the platen. Said oscillating plate 14 is formed with a depending arm 19 which is adapted to be actuated by suitable connections from the universal bar of the machine.

The back-spacer mechanism proper, as shown, includes a member designated gen.- erally by the reference A; an operating linl; B; a return spring C; and a second spring D.

The member A is of special stamped and formed construction. Said member A is formed with an elongated normally horizontally extending slot 50 providing a slidable pivotal. connection in conjunction with the pivot screw 5.1 which is carried by the plate bracket 87. Extending in the same general horizontal plane, and on the opposite side of the pivot 51 to the slot 50 is a finger 52, which is inwardly offset from the main plane of the member A, as indicated at 52 in Figs. 3 and 1. Said finger 52 is rounded, as indicated at 58, to thereby provide a cam adapted to ride upon and along a horizontally extending shelf or ledge 54, which is preferably formed integrally with the bracket plate 37 by suitably stamping the latter, as will be clear from an inspection of igs. S and e. In normal position of the parts, said cam 53 has its lowermost point somewhat below the upper surface of the shoulder 5d and slightly spaced therefrom to the right, as viewed in Fig. 8.

The member A, directly beneath the pivot pin 51 when the parts are in normal position, has a depending arm 55 which is inwardly ofi'set, as indicated at 56, and then provided with a normally horizontally-positioned extension 57, the free end of which is bent upwardly, as indicated at 58, and

then twisted at right angles so as to pro vide an upper tooth 59 adapted to co-operate with the teeth of the rack bar 29.- In normal position of the parts, as shown in igs. 1 and 3, said tooth 59 is positioned just below the teeth of the raclr bar, so as to clear the latter and avoid interference with the normal step-by-step advancement of the platen.

The elongated link 15 is pivotally connected with the depending arm 55, as indicated at 66, and is also inwardly offset, as indicated at 61, so that the main portion of the link B extends substantially parallel to, and relatively close to, the extension 57 of the member A. Said link B may be upwardly ofl'set as indicated at 62. At its free end, the link B is provided with a headed stud 68 upon which is loosely mounted an anti- :friction roller 64, the latter having rolling engagement with the upwardly extending arm 26 of the lever 25, as illustrated in Figs. 1 and 2. The enlarged head of the stud 63 serves to keep the link and arm 26 in operative relation. To confine the link B to a the ends thereof over suitable studs 68 and 69 formed on the member A and link B, respectively. Said spring D is an expansion spring normally tending to swing the member A in a clockwise direction about the screw pivot 51 when the parts are in normal position, but which, on account of its being of lesser strength than the spring 0, produces a different action, as hereinafter explained.

The operation is as follows, assuming that,

the operation begins when all of the parts are in normal position. As the operator depresses the back-spacer key 13, the lever will be oscillated in a counter-clockwise direction about the pivot 26 from the position shown in l ig. l to the position shown in Fig. 2. At this point, it will be noted that this operation obtains regardless of the case shift position of the platen, and. further, that the connection between the link B and the lever 25 is such as to admit of the re moval and replacement of the platen ear-- riage without disturbing the back-spacer zueclmnism and without requiring any attention being paid thereto. As the lever 25 is swung, as above described, the link B is pulled toward tl e left. as viewed in Fee. 2 and 4:. Upon the initiation of the move ient of the link B, as above des ribed, and which is againstthe tension of the spring'C, the first effect is for the link B to sligl'itlv oscillate the member A in a clockwise direction about the screw pivot 51 and this action is cumulative with the action of the spring D. Said oscillation of the member elevates the cam and also sin'iultaneouslv and prior to any sliding movement of the member A, the tooth 59 of the latter is immediately projected into engagement with the corresponding; space between two teeth of the rack bar 29. Further oscillation of the memher 3.. is then prevented hv reason of the engagement of the tooth 59 with the rack i r, and. consequently, the movement of the ill; B toward the left compels the member to slide horizontally over the pivot 51, hich is permitted by reason of the slot 50. As the sliding movement of the member A. begins, the cam 53 rides up onto the fixed snoulder or ledge 54L. and then along the same until final. position is assumed, as: shown in Fig. 4. During this sliding movemerit, it will be observed that there is no possibility of the tooth 59 becoming disengaged from the rack bar, and, consequently, there can be no slip or skip of the platen in the back-spacing movement. In actual practice, the movement of the link B will be made such that the tooth 59, while engaging with the rack bar 29, will. move the latter and platen toward the left or in back-spacing direction a distance equal to two of the teeth of the rack bar 29.

During the back-spacing movement above described, it is evident that the ratchet 39 will be rotated in a counter-clockwise direction equal to two teeth ofthe ratchet wheel and the tooth thereof will slip over the tooth of the pawl 41 and advance from the )osition shown in Fi 1 to the position of the tooth l0 shown in Fig. 2. During this action, it will be observed that the pawl 41 has also been permitted a movement toward the right, as viewed in Figs. 1 and 2, from the position shown in Fig. 1 to the. position shown in Fig. 2, this movement being commensurate with the length of the slot l3.

Upon the operator now noving the pressure from the back-spacer key 13, the latfor will be retracted by the spring 13 and simultaneously the link B will start toward the right, as viewed in Figs. 1 to 4 of the drg-twings under the contra t? of the spring (3. During the initial portion of the return bvernetot of the parts, it will be ob served that the tooth 59 of the member A cannot become disengaged from the rack bar 29 because of the fact that the cam is still. riding upon the stationaryshelf or ledge 54-, and the parts are so proportionedlihattlie engagement of the tooth 59 with the rack bar maintained until theirack bar 29 has rcturnel a distance corresponding to the space of one'tooth of the rack bar At this point in the action, the pawl 4.1 will have a med its operative relation with the rat het wheel 39 corresponding to the posiher A. is then depressed so as to disengage I the tooth 59 from the rack bar 29. As the memb r A slides back to its normal posi tion, own in Fig. 3, and when it is prevented irom further sliding movement with respect in the pivot 51, the spring D, under its expanding action, insures the complete depression of the member A or oscillation in a counter-clockwise direction about the pivot 51, since the force of the expanding spring'D depresses the adjacent part of the to mow-i '&

link B and this in turnforces the oscillation of the member At about the pivot 51.

Ar m the preceding description, it will be observed that the arrangement is such as to positively and instantaneously compel the tooth 59 of the member A to engage the rack bar 29 upon the initiation of the backspacing operation; that this engagement between the tooth 59 and rack bar 29 is positively maintained during the remainder of the actuating stroke by reason of the cam 58 riding along the stationary shelf 5%; that during the return movement of the parts of the back-spacer mechanism, the tooth 59 is prevented from disengagement from the rack bar 29 until the pawl 41 and ratchet wheel 39 have entered into final operative relation and stop further movement of the platen toward the r' it, as viewed in Figs. 1 and 2; and that, on 'ing the final portion of the return movement of the parts, the arrangement compels the proper disengagement of the tooth 59 from the spacer rack bar 29. It will further be observed that the essential parts of the back-spacer mechanism inay all be assembled as a unit upon the plate bracket 8'? and said unit applied as such to the sub-frame of the platen carriage, thereby minimizing the cost of assembling. The sheet metal portions of the essential parts of the backspacer mechanism may be manufactured by the ordinary steps of stamping and forming in quantities at small expense, and, on account of the few parts involved, the arrangement is not likely to soon get out of order.

Another important feature of 111? invention to which I wish to call attention is the following. In present forms of backspacer mechanisms, it frequently occurs that a fast operator will strike the back-spacer key quickly and with considerable "force and immediately release it. This causes the platen to acquire a considerable momentum which carries it in a back-spacing direction more than is intended for the reason that the back-spacing pawl or other element becomes disengaged upon removal of the pressure from the backspacer key, and while the platen is still under momentum. With my construction this is impossible for the reason that the tooth 59 cannot be disengaged from the rack 29 so long as the cam 53 is riding upon the shelf In other words it is impossible to overthrow the platen with my construction during a back-spacing movement.

I have herein shown and described What I now consider the preferred manner of carrying out the invention, but the same is merely illustrative and I contemplate all changes and modifications that come within the scope of the claims appended hereto.

I claim 1. As an article of manufacture, a backpacer mechanism for typewriters, includ- 1 g: bracket adapted to be secured to the ten carriage, a back-spacer pawl pivotal ly and slidably mounted on said bracket, a connecting link pivotally attached to said pawl, and an er-zpansible spring interposed between said pawl and said link at points intermediate the pivotal mounting of the pawl and the pawl tooth proper thereof.

2. As article of manufacture, a backspacer mechanism for typewriters, includ- Tin wi have hereunto subscribed my name this 16th day of May, 1921.

MAX GAB-BELL. Witnesses CARRIE GAILING, ANN BAKER.

;: a bracket adapted to be secured to the p 

